1. Field of the Invention
Embodiments of the inventive concept relate generally to image processing, and more specifically to an image pixel apparatus and an image pixel control method.
2. Description of the Related Art
With technological advances of the electronic devices such as digital cameras, cell-phone cameras, optical sensors such as image sensors are improving functionalities in various aspects of their operation. In particular, demand for the enhancement of a dynamic range is increasing.
This is because, as image sensors such as optical sensors are mounted within mobile devices, the image sensors are designed to be compact or highly integrated in order to reduce the size thereof. Therefore, for example, in case of a CMOS image sensor, the size of a photodiode which is a light receiving unit is reduced, which results in a reduction in the quantity of received light, and accordingly, a dynamic range thereof decreases.
In an effort to meet the requirements for the image sensors, a method of using multi-exposure, a method of using logarithmic response, and the like, were proposed by Arthur Spivak, Alexander Belenky, Alexander Fish, and Orly Yadid-Pecht in IEEE Transactions on Electron Devices, Vol. 56, No. 11, November 2009, pp. 2446-2461.
However, the multi-exposure method has a probability in which a difference in a signal to noise ratio (SNR) causes noise in the process synthesizing a plurality of signals each having a different exposure time. In addition, the method of using logarithmic response may have difficulty in processing a digital signal after an analog-to-digital conversion (ADC), in comparison to a linear response.